http://reply.papertrans.cn/2/123/12240/12240-31.png
http://reply.papertrans.cn/2/123/12240/12240-32.png
Submitted on: 19 March 2009.
Revised on: 25 June 2009.
Accepted on: 17 August 2009.
___________________IMA Journal of Management Mathematics
Submitted on: 19 September 2016.
Revised on: 06 November 2016.
Accepted on: 24 December 2016.
___________________IMA Journal of Management Mathematics
http://reply.papertrans.cn/2/123/12240/12240-35.png
Submitted on: 10 December 2013.
Revised on: 14 February 2014.
Accepted on: 25 February 2014.
___________________IMA Journal of Management Mathematics